Integrated circuits are made using various fabrication technologies. Fabrication facilities can use semiconductor wafers as a starting material and produce finished integrated circuits. Integrated circuit fabrication facilities can have many different pieces of equipment for performing many different processing steps. Fabrication facilities can employ a single integrated circuit process or many different integrated circuit processes. Various processing steps can be employed in manufacturing an integrated circuit. Epitaxial deposition, oxidation, diffusion, ion implantation, thin film deposition, etching of various layers, and photo-lithography are some of the processing steps that can be used in manufacturing an integrated circuit.
Thin film deposition of polysilicon is used in the manufacture of some integrated circuits. Complementary Metal Oxide Semiconductor (CMOS) circuits, for example, can use patterned structures of a polysilicon layer as gates. Control of finished dimensions can be an important factor in controlling the performance of an integrated circuit. The length of the active gate of a CMOS device is one such dimension. Thus, controlling the active gate length of a CMOS device can determine the performance realized by the integrated circuit.